This question has been killing me for years, someone please help: How, in the course of human evolution, did we find it necessary to cook food? I don’t see how this practice can possibly be a function of “survival of the fittest”. Wild carnivores and omnivores don’t seem to get food poisoning from eating raw meat, right? Why do we? The only thing I could think of is that they eat it fresh (i.e. immediatley after it’s killed), but that doesn’t stop buzzards and other scavengers.
There are several different reasons.
(1) As you mentioned, cooking food kills parasites and bacteria, so cavemen that cooked didn’t get sick as often. The reason that it doesn’t happen is that most carnivores eat their kills immediately before it spoils, while humans tend to keep it around for a while
(2) Cooking allows food to last longer. Humans are not the best natural hunters, so they expended a lot of energy catching their food; they wanted to keep it around as long as possible. Raw meat spoils quickly, while cooked meat takes a bit longer. Once primitive humans figured out how to dry and smoke meats, they were really able to extend the shelf-life of their supplies.
(3) Cooked food tastes better. Yes, that may be a matter of opinion, but cooking definitely changes the taste of food. Primitive humans must have developed a taste for cooked food over raw. This hasn’t totally changed, of course. I myself still enjoy the occassionaly bit of raw hamburger, mad cow disease notwithstanding.
They do get food poisoning sometimes but many animals have evolved resistances and almost all animals are highly particular about what foods they eat, avoiding anything that is highly decomposed or smells of toxic compounds.
Why don’t scavenging animals get food poisoning?
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jawbreaker asks:
Fire was used by early hominids (probably by Homo habilis, although the art of making fire may not have originated until H. sapiens evolved) for a number of purposes, including cooking food, with the benefits described by Guy Propski. It will be observed that cooked food is usually tenderer (or raw food is tougher, depending on your point of view). Thus, Homo didn’t need the massive jaw muscles (and other skektal adaptations, such as the sagittal crest) that we see in anthropoids to this day. Slack-jawed adolescents (aren’t they all?) that would have earlier starved to death instead survived to pass on that trait to descendants. H. sapiens is, in essence, a species that has evolved to need cooked food.
Much the same answer can be given to the related question, “Why don’t we have impressive canines like chimpanzees and baboons?” We don’t need them; we can make spears, instead.
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I would add to the information already offered that humans do not need to cook food. There are many foods, including adequate sources of all nutrients, which humans can eat without cooking. Humans can develop immunities to some pathogens, as well, both as individuals, and collectively as populations.
What is more to the point is that there are many more foods which are edible for humans only when cooked, or which require much less energy to eat, and utilize when they are cooked. Human digestive systems are very efficient in absorbing fruits, and very tender vegetable materials, and meat (even raw). However, the tough hulls of grains, and coarse texture of many vegetables make them far more difficult to us as primary food sources. The use of heat to make those foods useful opens up many new sources of food to the species. It also prolongs the life of the individuals in the species beyond the age of their strongest teeth.
The advantage of cooking does not replace the ability to eat raw foods, it supplements it. Since natural fires were first “domesticated” the human species has been able to provide sustenance for itself in many areas which would have been uninhabitable without that advantage. More range, longer lives, and reduced exposure to pathogens comprise a very strong survival benefit. The genetic selection events are not necessary to encourage it, even in a statistical sense for populations of early hominids. The changes that do occur happen later, and allow the shape of the head to change, allowing increased vocal ranges, and increases in cranial capacity. Those are just side effects, at first.
Tris
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That’s a very good point, Tris. Evolution isn’t always about need, but rather opportunity. Humans could survive on food as found au natural, but it would be a pretty rough existance. Cooking provides access to more nutrition, less loss of material (through spoilage, etc.), and a more efficient use of food material.
And it tastes great!
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In addition, most food gets softer and easier to eat if you cook it. That allowed us to eat food which had previously been too hard to eat. Fish and many vegetables are soft enough to eat raw, but uncooked meat is rather tough and uncooked grains are pretty much inedible.
scr4–you just reminded me of another factor: tooth loss. Primitive man would have been subject to tooth loss at an early age, thanks to general unsanitary conditions. Before cooked food, it would be damn near impossible for a toothless (or near toothless) hominid to eat. Post-cooking, it’s a different story. Not only does cooking make meat and grains softer, it also made possible the invention of soup. Now older hominids that would have died from starvation or malnutrition could live longer, have more baby hominids, etc.